1. Field of the Invention
The present invention relates to an internal combustion engine which is equipped with a sub-suction path for generating a swirl (i.e., a vortex flow) of suction gases in the combustion chamber.
2. Description of the Prior Art
Recently, internal combustion engines for automobiles are required not only to clean the exhaust gas but also to improve the rate of fuel consumption. For these requirements, exhaust gas recirculation (EGR) and a lean combustion are frequently employed. In order to prevent combustion fluctuations and misfiring while satisfying both the requirements for EGR and lean combustion, it is known to increase the burning velocity.
In order to increase this burning velocity, there have been recently proposed several intake systems, in which a sub-suction path is provided separately of the main suction path and is made to inject a gas into the combustion chamber thereby to generate a swirl of the suction gases in the combustion chamber.
However, the intake system provided with that sub-suction path is still being developed.